Conventionally, an actuator for a pickup has been employed as a mechanism for recording data onto an optical recording medium and/or playing back the contents thereof. Such the actuator for a pickup may have various types of constructions. In recent years, among various types of actuators for pickups, studies have been conducted on those capable of recording data onto an optical recording medium and/or playing back the contents thereof at a higher-x speed.
For example, such the actuator for a pickup is equipped with a lens holder for supporting an objective lens, a magnet, and the like, a plurality of drive coils for driving the lens holder, a base, and four linear elastic members each connected at both ends thereof between the lens holder and the base. The lens holder is so supported as to be able to rock in a focusing direction and a tracking direction (e.g., Patent Document 1).
This actuator for a pickup has been drawing attention especially for its advantages in weight saving and enhancement of bandwidth.
In this actuator for a pickup, there is a conventional art in which two of the linear elastic members which are adjacent to each other when viewed from the focusing direction are disposed in a “slanting manner” such that a dimension between connection portions of the linear elastic members connected to the base is larger than a dimension between connection portions of the linear elastic members connected to the lens holder, in view of saving space and improving rolling frequency characteristics. In the actuator for a pickup of this type, two of the linear elastic members which are adjacent to each other when viewed from the tracking direction are disposed in parallel to each other such that a dimension between the connection portions of the linear elastic members connected to the base is equal to a dimension between the connection portions of the linear elastic members connected to the lens holder.
The aforementioned actuator for a pickup may have six or more linear elastic members (Patent Document 2).
In the actuator for a pickup which has six linear elastic members as described above, the six linear elastic members are parallel to one another, and line segments linking the connection portions of the linear elastic members on an actuator base side and line segments linking the connection portions of the linear elastic members on a lens holder side form an oblong, respectively.
[Patent Document 1]: JP 2001-229555 A (FIGS. 15 and 16)
[Patent Document 2]: JP 08-273179 A (paragraph [0031])